Many computerized systems designed for spatial user interactivity require the tracking of the user activity. Specifically, systems based on cameras, for tracking objects that are manipulated by user are known in the art. These tracking systems in conjunction with the user manipulated objects serve as computer input devices.
U.S. Pat. No. 6,363,160 which is incorporated herein by reference in its entirety discloses a method of interfacing with an electronic system. The method includes receiving images from a camera. Then, a portion of at least one image from the camera is tracked. A pattern in the tracked portion of the image is recognized. Thus, the electronic system is controlled based on the recognized pattern.
U.S. Pat. No. 6,760,465 which is incorporated herein by reference in its entirety discloses a automated object tracking system for tracking a colored object through a series of frames of data. The system has a first image source device to provide a data array of pixels of a digital image. A second image source device provides a binary image of the data array. The system utilizes an analysis system to create a first histogram for rows of the binary image. Each histogram is thresholded, and is utilized thereafter to estimate the center of a tracked object in the binary image.
U.S. Pat. No. 7,113,193 which is incorporated herein by reference in its entirety discloses a hand-manipulated prop is picked-up via a single video camera, and the camera image is analyzed to isolate the part of the image pertaining to the object for mapping the position and orientation of the object into a three-dimensional space, wherein the three-dimensional description of the object is stored in memory and used for controlling action in a game program, such as rendering of a corresponding virtual object in a scene of a video display. Algorithms for deriving the three-dimensional descriptions for various props employ geometry processing, including area statistics, edge detection and/or color transition localization, to find the position and orientation of the prop from two-dimensional pixel data. Criteria are proposed for the selection of colors of stripes on the props which maximize separation in the two-dimensional chrominance color space, so that instead of detecting absolute colors, significant color transitions are detected. Thus, the need for calibration of the system dependent on lighting conditions which tend to affect apparent colors can be avoided.